Blame it on a "case of the Mondays" or perhaps a rough night out on the town, but for many of us getting a good night's rest isn't nearly as simple as it sounds. We get into bed and close our eyes expecting our feeling of being tired to translate into restful sleep; but for millions of Americans, getting to sleep, staying asleep, or getting quality rest simply isn't possible.

A problem too large to push under the covers
According to the National Sleep Foundation, insomnia is the most common sleep complaint in the U.S. Coming in two forms -- an acute form that usually abates after a short period of time, or a chronic version that can last for months or years -- insomnia affects between 30% and 40% of the U.S. population during the year based on research by the National Center for Sleep Disorders Research.  

Insomnia

Source: Alyssa L. Miller, Flickr.

Putting that figure into context, in a given year around 100 million people in the U.S. alone are having a hard time getting the proper amount of sleep needed to recharge their body. Without adequate rest, people exhibit a higher incidence rate of depression; run a higher risk of developing health complications; and miss more work than those with no sleep disorders.

What's really depressing about insomnia, more so than the actual disorder itself, is just how unsuccessful many insomnia drugs have performed over the past decade.

Understandably, there are often ulterior conditions that can lead to insomnia rather than the insomnia being the dominant disorder. Being pregnant, for instance, can lead to insomnia in women. Certain medications, such as those taken for heart disease and high blood pressure, and even treatments for the common cold, can lead to loss of sleep. But, even taking that into account, the breakthroughs in sleep medication over the past decade have been severely lacking.

One disappointment after another
Take Transcept Pharmaceuticals' Intermezzo, for example. It was approved by the Food and Drug Administration in late 2011 to treat insomnia characterized by waking up and not being able to fall back asleep. On paper, this drug should be selling like hotcakes. In Transcept's most recent quarter, it recognized only $500,000 in net royalty revenue from the sale of Intermezzo. However, it also spent $6.3 million with marketing partner Purdue Pharma on a direct-to-customer advertising campaign (which didn't do very much as you can see) and resulted in negative $5.8 million in revenue. With notoriously high co-pays, Intermezzo appears down for the count.

A similar drug was approved in 2010 by the now-defunct Somaxon Pharmaceuticals known as Silenor. Targeted as a sleep maintenance drug (one designed to keep patients asleep once they fall asleep), investors had high hopes and rocketed shares of Somaxon as high as $12 per share, but hope faded quickly. Somaxon partnered with Procter & Gamble (NYSE:PG) shortly after Silenor's approval, but not even its experienced marketing team could invigorate sales. Worse yet, Somaxon left the door wide open for P&G to exit the partnership as it saw fit since it was responsible for nearly the entire burden of marketing costs. P&G essentially worked out a "we'll stick around if things go well, but you're taking the heat if sales stink" type of deal.

Even the successful sleep aids have come under scrutiny in recent months by the FDA. In a ruling earlier this year, the FDA required sleep disorder drugmakers that develop drugs containing the active ingredient zolpidem, such as Sanofi's (NYSE:SNY) top-selling Ambien, to cut their recommended dosage in half. This comes on the heels of numerous reports of auto accidents caused by an impairment of the sleep aid the following day. Although this move shouldn't affect Ambien sales, or sales of other sleep aids using the active ingredient zolpidem in theory, it's a visible knock against their safety over the short term.

Do insomniacs have any hope?
If you've been wondering whether insomniacs have any hope left, it just may come in the form of Merck's (NYSE:MRK) experimental drug suvorexant. Last month suvorexant went before the FDA's panel and received a generally positive review of 12 to 4 that it was effective in maintaining sleep for patients. However, like Ambien, the FDA did echo one bit of concern about suvorexant's dosing, noting that 11% of the nearly 1,300 subjects who took higher doses of the sleep aid in trials exhibited somnolence (essentially a state of near-sleep). At lower doses, somnolence was reduced to just 7%.

With peak sales estimated at approximately $700 million in a $2 billion industry, suvorexant has a shot at being a dominant treatment -- assuming it is eventually approved and doesn't stumble off out of the gate.

While history is certainly not on the side of sleep-aids drugmakers, I feel that the progress of suvorexant is worth keeping a close eye on. I believe the big key to its success will be whether insurers latch onto the treatment en masse, ultimately reducing user co-pays and out-of-pocket costs. In the meantime, though, it looks like the waiting game will continue for insomnia suffers looking for new treatment options.

Fool contributor Sean Williams has no material interest in any companies mentioned in this article. You can follow him on CAPS under the screen name TMFUltraLong, track every pick he makes under the screen name TrackUltraLong, and check him out on Twitter, where he goes by the handle @TMFUltraLong.

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